Studies have shown that higher partial pressure of oxygen in commercial aircraft cabins provides improved comfort for passengers and crew. Simply put, for a given ambient air pressure, higher partial pressure of oxygen corresponds to a higher percentage of oxygen in the cabin air. Higher partial pressure of oxygen can also be achieved by increasing the pressurization of the cabin air.
Onboard oxygen generation systems (“OBOGS”) are traditionally used to generate an oxygen supply for flight crew masks and possibly other onboard systems. Although an OBOGS can be utilized to introduce higher levels of oxygen into an aircraft cabin, such use is not economically viable in comparison to the use of pressurization to increase the partial pressure of oxygen in the cabin.
Onboard inert gas generation systems (“OBIGGS”), such as nitrogen generation systems (“NGS”), can be utilized to reduce the combustibility of aircraft fuel tanks. An NGS produces nitrogen, which is fed into the fuel tanks, and oxygen enriched air as a byproduct. In traditional applications, the oxygen enriched air is treated as waste and is released into the environment. In an attempt to increase the partial pressure of oxygen in an aircraft cabin, this oxygen enriched air may be reinserted into the cabin at cabin ambient pressure (which is a relatively high absolute pressure compared to ambient pressure at high altitudes). Such recycled use, however, is not practical because an NGS relies on a pressure drop to ambient to increase flow and efficiency. In addition, such recycled use is less efficient in comparison to the use of pressurization to increase the partial pressure of oxygen in the cabin.
Accordingly, it is desirable to have an efficient and economical system for increasing the partial pressure of oxygen in an aircraft cabin. In addition, it is desirable to have a system for processing aircraft cabin air, where the system recycles the byproduct of an OBIGGS. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.